the only champ select "troll" is the player who steals your champion and then doesnt swap it with you or bans your champion and then tells you they didnt want you playing that champion.
there are the champ select griefers that end up upset over the trolls and then intentionally lock something they think will hurt the team while declaring that theyre locking in champion to try and hurt the team - usually the conversation goes "blame _______ for ____ i'm going _ anyway"
then there are the lane thieves who purposely steal someone's lane and tries to force them to go to a different lane even though lanes are assigned.
it's not trolling if the player trades you the champ or actually wants to play the champ, chooses an unusual champ for a lane.
it is still negative behavior to be afk whether that is physically or mentally. pay attention guy. accidentally banning your teammates champion or accidentally neglecting your lane is still negative behavior.